package com.hmdp.service.impl;

import cn.hutool.core.lang.UUID;
import cn.hutool.core.util.BooleanUtil;
import com.hmdp.service.ILock;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;

import java.util.Collections;
import java.util.concurrent.TimeUnit;

public class SimpleRedisLock implements ILock {


    private final String name;

    private final StringRedisTemplate stringRedisTemplate;

    public SimpleRedisLock(String name, StringRedisTemplate stringRedisTemplate) {
        this.name = name;
        this.stringRedisTemplate = stringRedisTemplate;
    }

    private static final String KEY_PREFIX = "lock:";
    private static final String ID_PREFIX = UUID.fastUUID().toString(true) + "-";

    private static final DefaultRedisScript<Long> UNLOCK_SCRIPT;

    static {
        UNLOCK_SCRIPT = new DefaultRedisScript<>();
        UNLOCK_SCRIPT.setLocation(new ClassPathResource("unlock.lua"));
        UNLOCK_SCRIPT.setResultType(Long.class);
    }


    @Override
    public boolean tryLock(long timeout) {
        // 获取线程标识
        String threadId = ID_PREFIX + Thread.currentThread().getId();
        Boolean b = stringRedisTemplate.opsForValue().setIfAbsent(KEY_PREFIX + name, threadId, timeout, TimeUnit.SECONDS);
        return BooleanUtil.isTrue(b);
    }

    @Override
    public void unlock() {
        // 调用 lua 脚本
        stringRedisTemplate.execute(UNLOCK_SCRIPT,
                Collections.singletonList(KEY_PREFIX + name),
                ID_PREFIX + Thread.currentThread().getId());
       /* // 获取线程标识
        String threadId = ID_PREFIX + Thread.currentThread().getId();
        // 获取锁中的标识
        String id = stringRedisTemplate.opsForValue().get(KEY_PREFIX + name);
        // 判断标识是否一致
        if (threadId.equals(id)){
        stringRedisTemplate.delete(KEY_PREFIX + name);
        }*/
    }
}
